In the production of hydrocarbons from existing wells, it is often necessary to deploy high voltage, high amperage pumps, heaters and other types of electrical equipment in the well bore. Given the expense of modern drilling and production equipment, the ability to splice two cables together quickly and efficiently to install or to continue use of the electrical equipment in the well bore is crucial to the efficient production from the well.
Presently, splicing electrical cables together requires a technician to strip, crimp and hand wrap each electrical conductor to its complementary conductor and then to wrap the entire assembly with protective insulating sealing tape. Because of the bulk of the wrapping, splices on individual conductors were often staggered thereby permitting the overall width of the final splice to be thin enough to be inserted in the well bore. Splicing a cable in this manner, however, required five or more feet of cable to be exposed from the exterior armor protecting the cabling and required the galvanized armor to be rewound around the spliced portion to protect the splices. The high temperatures and pressures sustained by these splices led to early failures of the splice, which caused catastrophic arcing of the conductors through the wrapping on the splice. Gases penetrate the splice until the pressure of the dissolved gases in the intermolecular spaces of the materials and the pressure of the gases in the well bore reach an equilibrium condition.
Decompression occurs when the pressure outside the splice is reduced, causing the dissolved gases inside the splice to rapidly expand and thereby escape from the splice. Decompression results both from the reduction of the fluid column level height within the well resulting from pump activity; or, from cycling the well off for either pump-off control, or removal of the wellhead without sufficient time for the well to slowly decompress when pulling the conductor and pump system from the well for servicing. Rapid decompression, especially when exacerbated by repeated cycling, results in cracks in the cabling and in the splice, which can lead to failure of the splice or cable from expansion of the dissolved gases within the splice. Ideally, the splice should contain a connection that decompresses without trapping entrained gases causing tears in the splice, thereby minimizing arcing from one conductor to another.
Splices have had a tendency to fail when the pump is shut down and pressure rapidly released on the well head, permitting entrained air and gases within the splices to decompress and blown the splice apart, causing the catastrophic arcing of the conductors. Because of these problems, the industry has long sought a cable splice assembly permitting rapid installation and which could be installed in wet weather, and which prevented premature arcing failure of the electrical conductors upon decompression of the well.